# Generic directives/plugins syntax **URL:** \ **Category:** Extensions\ **Created:** [September 6, 2014, 9:50am UTC](https://talk.commonmark.org/t/generic-directives-plugins-syntax/444 "2014-09-06T09:50:24Z")\ **Posts on this page:** 1\ **Showing post:** 100
**Author:** ![nexussays](https://cdn.commonmark.org/user_avatar/talk.commonmark.org/nexussays/32/473_2.png) [@nexussays](https://talk.commonmark.org/u/nexussays)\ **Post date:** [October 9, 2014, 10:05pm UTC](https://talk.commonmark.org/t/generic-directives-plugins-syntax/444/100 "2014-10-09T22:05:42Z")
The use-case you used is the one I _explicitly said_ is in-keeping with the spirit of Markdown. > For example, I like extending `![]()` to mean “embed this resource” not “create an image tag”. It is keeping with its semantic use and the spirit of MD. A theoretical `!youtube[Funny video](http://youtu.be/dQw4w9WgXcQ)` would render as “!youtube[Funny video](http://youtu.be/dQw4w9WgXcQ)” which, IMO, is a perfectly acceptable fallback since it still provides a link to the content and the exposed exclamatory declaration isn’t so jarring as to render the output confusing or meaningless. But to specifically answer your straw man, no, I do not see any problem with this either: ```` ```youtube http://youtu.be/dQw4w9WgXcQ ``` ```` It would render as an embed where a “youtube” plugin is available and as ``` http://youtu.be/dQw4w9WgXcQ ``` where no such plugin is available, it’s a reasonable fallback and non-breaking to existing implementations. * * * But even that doesn’t answer a multitude of other questions: - Why would you resolve this to a `
` element? - Why an iframe instead of an object or video embed? - What if someone else wanted a different output format? Are there now multiple different potential outputs for “!youtube” depending on what site you’re posting on or what parser you’re using? --- _[View the full topic](https://talk.commonmark.org/t/generic-directives-plugins-syntax/444)._